US2855381A - Organopolysiloxane amides - Google Patents

Description

United States Patent a ORGANOPOLYSILOXANE AMIDES Leo H. Summer, University Park, Pa., assignor to Dow Corning Corporation, Midland, Mich., a corporation of Michigan No Drawing. Application July 18, 1955 Serial No. 522,825

8 Claims. (Cl. 260-465) This invention relates to novel or organopolysiloxanes having amide groups attached to the silicon through carbon atoms.

This application is a continuation-in-part of applicants copending application Serial No. 512,329 now abandoned, filed May 31, 1955.

Heretofore amide groups attached to silicon atoms have been disclosed and claimed in U. S. Patent 2,610,198. These compounds have four organic groups attached to the silicon and hence cannot be polymerized into polymeric siloxanes. Consequently, the utility thereof is limited as compared with the utility of the compounds of this invention.

One of the difliculties which has long plagued the organosilicon art has been the fact that organosilicon polymers and resins are deleteriously affected by hydrocarbon solvents and oils. The heretofore employed resins and rubbers swell and will deteriorate when subjectedto these solvents. This is a serious defect for many applications which require multiple coatings or for those applications which require sealing in contact with such solvents and oils. As a result there has been a prolonged and intensive search for organosiloxane materials which will not deteriorate or which show greatly improved stability in contact with hydrocarbon solvents. Applicant has found that the compositions of this invention, both homopolymers and copolymers, show a greatly reduced swell when subjected to the solvents.

It is the object of this invention to provide novel organopolysiloxanes which show improved resistance to hydrocarbon oils and solvents. Another object is to provide materials suitable for use in siloxane rubbers which give improved strength. Other objects and advantages will be apparent from the following description.

This invention relates to polymeric siloxanes of the unit formula R R HzNO C C H(CH2)nSiO in which R is methyl or hydrogen, n has a value from 1-3 inclusive and R is a monovalent hydrocarbon radical free of aliphatic unsaturation.

The polysiloxane amides of this invention in which n is 1 may be prepared starting with the acids disclosed and claimed in applicants copending application Serial No. 522,826 filed simultaneously herewith entitled, Organopolysiloxane Acids and Esters, which is hereby made a part of this specification. the polysiloxane amides from these polysiloxane acids involves the treatment of the acids with SOCl to form the corresponding polysiloxaneacylchlorides which are then treated with ammonia gas to replace the chlorine to form the corresponding amides. The resulting polymer is then washed free of HC1 and any ammonium chloride. Alternatively the amides of this invention may be pre pared from the corresponding nitriles disclosed and claimed in the applicants copending application Serial No. 522,827 filed simultaneously herewith entitled,

Organopolysiloxane Nitriles, which is hereby made a.

The preparation of Pate ted Oct. 1, 1958 part of this specification. The amides are prepared by hydrolyzing the nitriles with cold concentrated sulfuric acid. The nitriles shown in the aforesaid application are monomers having the general formula r I R NECCHUJHzhiCl,

and polymers of the unit formula such that the amide groups are not hydrolyzed. In general the interaction is best carried out under anhydrous conditions but water may be present if the temperature employed is low (i. e. about room temperature).

For the purpose of this invention the copolymers can range in composition from .l99.9 mol percent siloxane' .units of the formula R R HzNOCCH(CH2)nSiO :and from .199.9 mol percent siloxane units of the formula R,,.SiO

- in which R, R, R" m and n are as above defined. These copolymers may contain 1 or more difierent types of .siloxane amide units and may contain any combination of units of the formula R"SiO R" SiO and R"SiO There can be more than 1 type of R" groups attached to any 1 silicon atom.

For the purpose of this invention R can be any saturated aliphatic hydrocarbon radical such as methyl, ethyl, propyl, octadecyl or t-butyl; any saturated aliphatic hydrocarbon radical such as cyclohexyl and cyclopentyl; any aryl hydrocarbon radical such as phenyl, tolyl or xenyl and any aralkyl hydrocarbon radical such as =benzyl. .R" can be any monovalent hydrocarbon radical such as alkyl radicals such as methyl, ethyl, butyl and octadecyl; alkenyl radicals such as vinyl, allyl and hexenyl; cycloaliphatic radicals such as cyclohexyl and cyclohexenyl; .aralkyl hydrocarbon radicals such as ibenzyl and aromatic hydrocarbon radicals such as phenyl, tolyl, xenyl and tain any of the conventional fillers, oxidation inhibitors,

compression set additives and pigments which are normally employed in'silicone rubbers.

The following examples are illustrative only not be construed as limiting the invention which is properiy delineated in the appended claims. The symbols Me,

'Ph, and Vi have been used hereafter in accord with their usual meanings of methyl, phenyl, and vinyl radicals'respectively.

and should Example 1 A sample of the polysiloxane acid having the unit formula Mg. Hopoomomsio was treated with an excess oi 'thionyl chloride and the excess thionyl chloride was subsequently removed to give 41 g. of the polysiloxane acid chloride of the formula of the unit formula Me. HZNO oongornsio Example 2 7.5 parts by weight of the polysiloxane amide. of Example 1 was dissolved in 100 ml. of concentrated sulfuric acid. 16.9 parts by weight of octamethylcyclotetrasiloxane was added and stirring was continued until the solution was complete. The mixture was poured with stirring into cracked ice. The solution turned milky and soon a white polymer precipitated. This polymer was separated from the water by filtration and was broken up into small pieces and washed with water to remove all of the sulfuric acid. The resulting product was a rubbery material which when thoroughly dried and shaped into a ball bounced like natural rubber. This material was a copolymer of 80 mol percent dimethylsiloxane and 20 mol percent Me HzNO C CHzCHzSiO units A sample of:this polymer was immersed in isooctane at 25 C. and thepercent increase in volume was determined and; found to, be 23.8 percent after 30 minutes,

48.4 percent after 2-; hours and 78- percent after 5.5

hours. By; contrasta partially vulcanized copolymer of vinylmethylsiloXane; anddimethylsiloxane swelled 210 percentafter, 2 hoursimmersion in isooctane at 25 C.

7 Example 3 Me H3NO CHZIC HrSiO units.

A piece of this material wasimmersed in isooctane at;25 C. and: afterI /z hour. the volume had increased 753 percent and after. 2 hoursit hadincreased 174 per-.

cent. Bycontrast a partially. vulcanized copolymerlof, methylvinylsiloxanc'. and-J- dimethylsi-loxane increased in. volume- 100 percent. in. 3th minutes. and 210 percent in.

2 hours under the same conditions.

Example 4,

5.2 parts by weight of the copolymer of Example 3 was interacted with 28 parts by weight of octamethylcyclotetrasiloxane by heating a mixture of the two with solid NaOH until a gummy, viscous material was obtained. The resulting polymer was ground in a mortar and washed-with water. After dryingthe polymer was an elastic rubbery material of good tensile strength.

This material was a copolymerof about 1.2 mol percent Me I-IzNOCCHeOHzSlO units and. 98.8 mol percent dimethylsiloxane units.

Example 5 When a polysiloxane acid of the formula is employed in theprocedure of Examplel a solid polysiloxane amide of the unit formula Ph HeNOCCHzCHzSiO is obtained.

When this material is interacted in equimolar amounts with a copolymer of mol percent ViSiO mol percent PhMeSiO, 10 mol peercent Ph SiO, 63 mol percent Me SiO and 2 mol percent Me SiO in accordance with the procedure of Example 2, a viscous polymer of the composition 5 mol percent ViSiO 7.5 molpercent PhMeSiO, 5 mol percent Ph SiO, 31.5 mol percent Me SiO, 1 mol percent Me SiO; and 50 mol percent Ph HZN O C CHzCHzSiO is obtained.

Example 6 28 g. of the polysiloxane Me Me (HOOCCHCHzSiO):

and 33 g. of thionyl chloride were mixed and shaken. Evolution of gas occurred. When the reaction had sub sided, the mixture was heated to 110 C. When all 0f' the polymer had dissolved the mixture was heated on a steam bath for 16 hours.

a quantitative yield of the compound.

Me Me (010 0 CH0 112810):

48 g. of this polyacylchloride was dissolved in 600 cc.

Gaseous ammonia was bubbled through the...

of ether. solution for minutes. Sufiicient ice was added to dissolve the ammonium chloride. The resulting solution was filtered and washed with water until neutral. g. of a solid polymeric amide of the unit formula HQN 0 c iiiro I2 and mol percent Me SiO was obtained.

Example 7 .5 mol of the compound Me NC (CH2)sSiCl2 wasmixedwith ml. of glacial acetic acidandlSO; ml. of.;concentrated MCL: The mixture wasrefluxed;

for ,2 hours.. The. mixture .was...distilled;untili vigorous The excess thionyl chloride was removed at reduced pressure and there was obtained bumping occurred whereupon the residue was filtered. The filtrate was a clear, viscous liquid which was extracted with water to remove ammonium acetate. Benzene was then added and the product was dried by azeotropic distillation. The resulting product was the acid siloxane of the unit formula Me HO O C (CHa)iSiO 2 mols of thionyl chloride were mixed with this acid and the material was allowed to react for several hours. When gas evolution had ceased the mixture was heated to 50 C. 2 hours. The excess thionyl chloride was removed by vacuum distillation and there was obtained a clear, slightly yellowish, viscous fluid of the unit formula Me Cl0O(CHi):SiO

This acyl halide was dissolved in 600 ml. of ether and ammonia gas was bubbled through the mixture for 40 minutes. Ice was added to dissolve the ammonium chloride and the mixture was filtered. There was obtained a white, solid, elastic polymeric material of the unit formula Me HzNO C(CHmSiO 21.3 g. (.132 mol) of this polysiloxane amide were dissolved in 100 ml. of concentrated sulfuric acid. 39 g. (.132 mol) of octarnethylcyclotetrasiloxane were added to the solution. The resulting homogeneous solution was poured with stirring onto ice and an oily polymeric material separated. The mixture was extracted repeatedly with ether and the ether solution was evaporated to dryness to give a sticky, tough, elastic copolymer having the composition 20 mol percent HzNOC(CH1) i%) and 80 mol percent Me SiO.

Example 8 10 g. of the compound were dissolved in 35 g. of concentrated sulfuric acid. The chlorosilane reacted rapidly with the acid to give HCl. The nitrile groups were simultaneously hydrolyzed to. amide groups. After standing for 30 minutes the reaction mixture was poured onto 30 g. of ice. The organic layer was separated and allowed to stand whereupon a hard, rubbery polymer of the unit formula Me HrNO C (OHa)4SiO was obtained.

This material was also prepared from the siloxane acid of the unit formula Me HO0C(CHa)|SiO v by the steps described in Example 7.

10 g. of the polyamide siloxane was dissolved in 50 ml. of concentrated sulfuric acid and 22.5 .g. of octamethylcyclotetrasiloxane were added to the solution. Ice was added to the solution until all of the polysiloxane precipitated. A copolymer was separated from the acid layer and washed with water to give a sticky, rubbery copolymer having the composition 20 mol percent and 80 mol percent Me,Si0. That which is claimed is: 1. A polymeric siloxane of the unit formula in which R is selected from the group consisting of methyl radicals and hydrogen atoms, R is a monovalent hydrocarbon radical free of aliphatic unsaturation, and n has a value from 1-3 inclusive.

2. A polymeric siloxane of the unit formula where the symbol Me represents a methyl radical.

3. A polymeric siloxane of the unit formula Me HQNO C(CH2)aSiO where the symbol Me represents a methyl radical.

5. A polymeric siloxane of the unit formula Me HaNO C(CHz)4SiO where the symbol Me represents a methyl radical.

6. A copolymeric siloxane consisting of from .1-99.9 mol percent siloxane units of the formula R HzN0ccH 0Hz)..si0 wherein R is selected from the group consisting of methyl radicals and hydrogen atoms, R 'is a monovalent hydr-ocarbon radical free of aliphatic unsaturation and n has a value from 1-3 inclusive and from .l-99.9 mol percent siloxane units of the formula R",,,SiO T in which R is amonovalent hydrocarbon radical and m has an average value from 1-3 inclusive.

7. A method for the preparation of 'organopolysiloxane amides which comprises dissolving an organosilicon nitrile selected from the group consisting of nitriles of the formula where R is selected from the group consisting of methyl radicals and hydrogen atoms, R is a monovalent hydrocarbon radical free of aliphatic unsaturation, and n has a value of from 1 to 3 inclusive, in concentrated sulfuric acid, and contacting the resulting solution with water in a liquid phase.

References Cited in the file of this patent UNITED STATES PATENTS Sommer Aug. 19, 1952 Speier Nov. 15, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 2,855,381 October '7, 1958 Leo Ha Sommer It is hereby certified that error appears in the printed specification that the said Letters of the above numbered patent requiring correction and Patent should read as corrected below.

a a a Column 1, llne l5, strike out "or"; column 2, line 40, for "R 510 read. R SiO colunm 4, line '74, for "MCl" read as I-ICl 5 column 5 line 12, after "50 Cu insert for u Signed and sealed this 13th day of January 195?o SEAL) ttest: KARL HQ AXLINE ROBERT c. WATSON Commissioner of Patents Attesting Officer

Claims (2)

1. A POLYMERIC SILOXANE OF THE UNIT FORMULA

7. A METHOD FOR THE PREPARATION OF ORGANOPOLYSILOX ANE AMIDES AMIDES WHICH COMPRISES DISSOLVING AN ORGANOSILICON NITRILE SELECTED FROM THE GROUP CON SISTING OF NITRILES OF THE FORMULA